Environmental Change: Artificial Plantation Of Mangrove Plant Species In Sundarban

The world largest single tract mangrove forest, the Sundarbans of Bangladesh is very important ecologically, biologically and economically. The sustainability of this forest has been jeopardized due to change in the ecological conditions.

The Mangrove Silviculture Division of the Bangladesh Forest Research Institute has been conducting research on the silvicultural aspects in the natural mangrove forests (Sundarbans) of the country since 1977. By this time, some technologies have been generated with an objective to afforest some vacant areas (poorly regenerated areas, char lands, canal and river banks) of the Sundarbans by mangrove plant species. The use of these technologies will help protect the embankments, stabilize the newly accreted char lands, increase the productivity and conserve the biodiversity of the Sundarbans. The nursery and plantation techniques of some mangrove plant species of the Sundarbans are as follows:¬

1. Nursery and Plantation Technique of Golpata (Nypa fruticans)

Objectives:-

 This technology can be applied for the protection of the river banks.
 Rehabilitation of the newly accreted char lands of the Sundarbans.
 To meet up the demand of the widely used thatching materials of the people of south-western part of the country.
 To increase the plantation area of Bangladesh

Seed collection and Preservation:-
Mature (dark brown) and viable seeds should be collected by cutting the fruit bunches from at least 5 years old plants during the month of February to April. The bunches should be stored in a moist place for 3-4 days, and subsequently the seeds should be detached from the stalk by gentle pressure.

Methods of raising seedlings:

There are two methods have for golpata plantation. They are:

a) Nursery bed method
The nursery site should be selected in a place where inundation by brackish water occurs only by spring high tides. The seeds should be dibbled in the bed at a spacing of 5 cm. The nursery area should be protected by fencing from damage by wild and domestic animals. Regular weeding is necessary. Watering is also necessary if there is no tidal inundation.

b) Ditch method:-
The site should be selected near a canal side in a ditch. Seeds in the nursery bed should be spread in such a way that one does not overlap another. The nursery site should be protected by fencing to protect the buoyant seeds from washing out by tidal water.

Planting and Silvicultural treatment
The site with gentle slopes along the banks of the rivers or in the newly accreted char lands which are inundated by all tides in the less saline and moderately saline zones should be selected. Two to three months old seedlings attaining heights of 25-30 cm should be planted at a spacing of 2 m × 2 m during July to August when there is minimum salinity. Weeding should be done 4 times in the 1st year, 3 times in the 2nd year and 2 times in the subsequent years. In the 3rd year, pruning and thinning is necessary to keep the seedlings 400 to 500 per hectare with removal of rhizomes of the thinned plants.

Bismark Bangali

BSC in Agrotechnology

Khulna University, Khulna, Bangladesh.

bismark_kubangali@yahoo.com